1. Field of the Invention
The present invention is directed to a lockup clutch for a hydrodynamic torque converter with a torsional vibration damper.
2. Description of the Related Art
A prior art lockup clutch is disclosed by FIGS. 1 and 2 of reference DE 41 21 586 A1. This prior art lockup clutch is arranged in a hydrodynamic torque converter axially between the converter housing and the turbine wheel. The lockup clutch has a piston which is arranged so as to be rotatable and axially displaceable on a turbine hub. The lockup clutch also acts, via a rivet connection, on driving means on a drive side for elastic elements of a damping device. The lockup clutch forms, with these driving means, a drive-side transmission element of a torsional vibration damper of the lockup clutch. The elastic elements in the form of circumferential springs couple the drive-side driving means with a driven-side driving means in the form of a hub disk which is provided with an inner toothing for meshed coupling with an outer toothing of a carrier which is fixed with the turbine hub so as inot to be rotatable relative to it. The driven-side driving means. together with the holder, forms a driven-side transmission element of the torsional vibration damper of the lockup clutch.
In this torsional vibration damper, the transmission elements which act relative to one another via the damping device operate in such a way that a complete frequency range can be filtered. However, torsional vibrations of a determined order cannot be overcome.
In another prior art vibration damper disclosed, for example, in FIG. 1 of DE 196 18 864 A1, a torsional vibration damper which is constructed with a drive-side transmission element in the form of a first flywheel mass and, rotatable thereto, a driven-side transmission element in the form of a second flywheel mass. Both flywheel masses have driving means for elastic elements of a damping device which act in the circumferential direction between the flywheel masses. The driven-side transmission element has a recess or cutout in which a compensation flywheel mass is arranged so as to be movable along a guide path. Both the guide path and the compensation flywheel mass are constructed with a curvature, so that a rolling movement of the compensation flywheel mass is carried out along the guide path when a torsional vibration is introduced. On the one hand, because of the two flywheel masses connected with one another by a damping device, a complete frequency range can be filtered with a device of the kind mentioned above, that is, amplitudes of different orders are damped, while, on the other hand. torsional vibrations of a determined order at determined amplitude magnitudes can be reduced by a determined amount in an outstanding manner due to the compensation flywheel mass.